Construction And Drug Release Research Of PH-sensitive Magnetic Targeting Drug-loaded Dendritic Polymer

pH-sensitive nano drug carriers possessing the pH-sensitive bond can reach the target tissue and make bond breakage occurs affected by the pH value, then the drug is released to kill the cancer cells. Polyamide-amine (PAMAM) dendrimers, have developed rapidly in recent years, is a new class of biomedical polymer materials with good biocompatibility and non-toxic and rich surface functional groups. The use of polyamide-amine (PAMAM) dendrimer nanoparticles for magnetic surface functionalization can increase drug loading efficiency. In this article, we introduce the different methods to obtain hydrophilic amide magnetic nanoparticles and characterization analysis, at last we choose the optimal magnetic nanoparticles to be grafted with PAMAM. The main contents are as follows:(1) We use chemical co-precipitation method and pyrolysis method to prepare Fe3O4magnetic nanoparticles. Oleic acid modified Fe3O4nanoparticles can be prepared by chemical co-precipitation method, and at the same time polyacrylic acid (PAA) modified magnetic nanoparticles are prepared by using pyrolysis method. Particles’dispersion and stability have been improved after modified with polymer, the diameter size of which is about10nm.(2) Two different amino-modified magnetic nanoparticles are prepared, and then using Michael addition reaction (Michael) of amino groups and amidation reaction of ester groups to graft the polyamide-amine dendrimers (PAMAM), which are biocompatible and non-toxic. The as-prepared Fe3O4/APTES/2.5GPAMAM and Fe3O4/mPDGs/2.5GPAMAM magnetic nanoparticles are characterized by their particle size, magnetic content, saturation magnetization and particle dispersion.(3) Doxorubicin is loaded on the Fe3O4/APTES/2.5GPAMAM and Fe3O4/mPDGs/2.5GPAMAM magnetic nanoparticles by hydrazone, and then drug release test is conducted in different pH buffers solution to simulate the vitro environment. Measured by UV, drug loading rate of Fe3O4/APTES/2.5GPAMAM magnetic nanoparticles is17.33%, drug loading rate of Fe3O4/mPDGs/2.5GPAMAM magnetic nanoparticles is18.06%, at the same time, the drug encapsulation efficiency of Fe3O4/APTES/2.5GPAMAM magnetic nanosphere is86.66%, the drug encapsulation efficiency of Fe3O4/mPDGs/2.5GPAMAM magnetic nanoparticles is90.3%. Through the curve, we can conclude that the last cumulative release rate of Fe3O4/APTES/2.5GPAMAM nanoparticles can be up to67.25%; the last cumulative release rate of Fe3O4/mPDGs/2.5GPAMAM nanoparticles can be up to74.69%.